how to calculate sum in vb.net

Question

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        dtProducts = New DataTable("Products")
        dtProducts.Columns.Add("ID", GetType(Int32))
        dtProducts.Columns.Add("Name", GetType(String))
        dtProducts.Columns.Add("Quality", GetType(Double))
        dtProducts.Columns.Add("Price", GetType(Double))
        dtProducts.Columns.Add("Sum", GetType(Double))

'---- this columns i need to calculate quality * Price= sum

        With dtProducts.Columns("ID")

            .AutoIncrement = True
            .AutoIncrementSeed = 1
        End With

        dsNorthwind = New DataSet("Northwind")
        dsNorthwind.Tables.Add(dtProducts)
        dgProducts.DataSource = dsNorthwind
        dgProducts.DataMember = "Products"

    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        dsNorthwind.WriteXml(xmlFile)

    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If File.Exists(xmlFile) Then
            dsNorthwind.ReadXml(xmlFile)

        End If

    End Sub
End Class

Answer 1

Just put the expression

...................................................

dtProducts.Columns.Add("Quality", GetType(Double))
 dtProducts.Columns.Add("Price", GetType(Double))

 dtProducts.Columns.Add("Sum", GetType(Double), "Quality*Price")

.........................................................

---

Arjun Paudel

Answer 2

Hi AgronSverkaj,

If you want to calculate the sum of certain column, you can write code like this:

Dim i As Integer

Dim total As Double = 0

For i = 0 To dtProducts.Rows.Count - 1

total = total + dtProducts(i)("Sum")

Next

MsgBox(total)

Does this works for you? If you have any questions or concerns, please update the thread and we will have a further discussion.

 

 

Best Regards

Yichun Feng

---

Please remember to mark the replies as answers if they help and unmark them if they provide no help.
Welcome to the All-In-One Code Framework! If you have any feedback, please tell us.

Answer 3

TextBox1.TextChanged 

Dim i As Integer

Dim total As Double = 0 

total = total + dtProducts(i)("Sum")             

      'The problem is Here 

MsgBox(total)

Answer 4

Hi AgronSverkaj,

Try this:
total = total + (CType(dt(i)("sum"), Double))

And if it doesn't work, please give the description of error message. So that we can better idea of you problem.

Best Regards

Yichun Feng

---

Please remember to mark the replies as answers if they help and unmark them if they provide no help.
Welcome to the All-In-One Code Framework! If you have any feedback, please tell us.

Answer 5

 

Dim i As Integer

 

Dim total As Double = 0

 

For i = 0 To dtProducts.Rows.Count - 1

total = total + (

CType(dt(i)("sum"), Double))

'By dt is error the msg is name dt is not declared this is dhe message of errore

Next

MsgBox(total)